Besides being a geological survey genius, Fang Xuanling once apprenticed at the Great Tang Gunpowder Bureau and spent some time learning the use of firearms and gunpowder.
However, due to youthful arrogance and clashes with his superiors, he was directly expelled from the Gunpowder Bureau, and later recruited by Liu Xian to become a guest of the Liu family.
When mining gold, if relying solely on manual labor, it would certainly take a long time, possibly months without digging several zhang deep, so Liu Xian secretly granted Liu Zhizhang the right to use black gunpowder for blasting.
Everything developed by the Gunpowder Bureau was considered a forbidden item by the court, only usable by the military and approved officials.
As a famous city in Jiangnan, Yangzhou Prefecture naturally had black gunpowder reserves, and Liu Xian, as the Prefect of Yangzhou, could secretly redirect a batch of black gunpowder outside, which became extremely plausible.
